Biocontrol performance evaluation of spontaneous mutants of Pseudomonas fluorescens VUPf5 generated during proliferation.

摘要

VUPf5 genetic stability as a superior strain (of the 900 bacterial strains that were isolated from the rhizosphere of different regions of Iran) for the control of take-all disease of wheat was studied. The genetic stability of the strain in terms of, whether or not, the mass and reproduction of bacteria in liquid medium was determined. VUPf5 produces some secondary metabolites such as extracellular proteases, phenazine antibiotic, siderophore, hydrogen cyanide and volatile metabolites. The regulatory GacA/GacS system has involved as an important system in the production of secondary metabolites in the biocontrol fluorescent Pseudomonas spp. During proliferation, different colonies of bacteria were found in terms of morphology, such as colour (white instead of orange) and shape (approximately flat and larger) of the colony; and media pH that in the mutants was higher, and the production of some metabolites, such as protease, HCN and phenazine was surveyed. Also, mutants in the genetic comparison with the wild type were different. VUPf5 and different colonies were detected in gacA and gacS genes. This paper appears in colonies with low efficiency in the production of secondary metabolites is related to mutation in genes gacS and gacA.